Sunday, December 28, 2014

Field Notes: Life Among Isle Royale Wolves

Climate Confidential

Overview

Nine wolves, two men, and a drive to upend the conventions of wilderness
protection to save an isolated group of nature’s most elusive
predators. As we explore the themes of limits and borders this month, we
talk to two wolf ecologists who study the ways that isolation can
both sustain and limit a predator-prey ecosystem.

Published December 20, 2014

BY MARY CATHERINE O’CONNOR

Isle Royale rises from the icy waters
of Lake Superior about 20 miles south of Ontario,
Canada. This far north, temperatures often drop below 15 degrees
Fahrenheit during winter. Since the late 1940s, gray wolves have carved out a niche on this narrow strip of
protected wilderness, feeding mostly on moose. Isle Royale wolvesPhoto: Rolf Peterson
Wolves first entered the island by way of
an ice bridge that connected the island to the mainland. The few who came,
thrived. Hunters at the time aimed to eradicate wolves
on the mainland, but on Isle Royale, wolves faced no predators.

The Isle Royale wolf population tends
to fluctuate as moose numbers rise and fall. But the most recent count,
last winter, found only nine wolves surviving on the island — close to
an all-time low — and
scientists say they saw no evidence of successful breeding this summer.
At its
peak, Isle Royale supported a population of at least 50 wolves. Moose,
meanwhile, have doubled their numbers to 970 individuals in just three
years.This annotated MODIS satellite image shows where an ice bridge formed during early 2014.
Wolf ecologist Rolf Peterson, 65, a
researcher with Michigan Technological University, has tracked wolf and moose
dynamics on Isle Royale since 1970. In partnership with population ecologist John
Vucetich, 43, he now leads research touted as the longest-running
study of any predator-prey system in the world. Over the years these wolves
have survived viruses, famine, and the occasional counterattack from a 700-pound
moose, but Peterson worries that climate change and a shrinking gene pool will
end the era of wolves on Isle Royale before the end of the decade.A wolf pack moves across breaking ice around Isle Royale. Photo: Rolf PetersonWorking
the Island

Each winter, Peterson climbs into a
small seaplane in Ely, Minnesota, with Vucetich, who joined the wolf-moose
research project in the early 1990s. Pilot Don Glaser flies the two scientists to
the island, which is also a
national park. For two months, the three men live in
a small lodge and spend many days in flight, chasing the radio signal from a
collared wolf that can lead them to sites where wolves and moose interact.

In the summer, Peterson and Vucetich
head to opposite ends of the island to study its diverse plants and mammals,
including snowshoe hares and beavers. When they find a moose or wolf carcass, they
perform a necropsy to discern the cause of death. But mostly,
Peterson and Vucetich observe and document life among some of nature’s most
elusive large carnivores.Rolf Peterson skis to the site of a moose carcass.Photo: John Vucetich
“In my first season on Isle Royale,” Vucetich
recalled, “Rolf gave me a list of things I needed to pay attention to and I
couldn’t even believe that it was possible to take two steps in an hour down
the trail and pay attention to all of these things.” They log the location
and activity of moose and wolves spotted in the field, and collect fecal
samples for genetic tests. They monitor other species, too. It’s important to
track the number of gray jays, for example, because they are important
scavengers of wolf-killed moose, explains Peterson, and so a drop in the number of moose
carcasses in a given season could in turn hurt the gray jay population.

“We spend an incredible amount of time just
getting into position to get a few seconds of observation,” Peterson said. “The
number of hours during any year that we actually spend watching wolves, you can
count those on one hand.”John
Vucetich measures a balsam tree, which is a dominant food source for
moose in winter. “Understanding the relationship between wolves and
moose depends greatly on also understanding the relationship between
moose and the forest,” Vucetich said.Photo: Leah VucetichThe
Old Grey Guy

In the late 1950s and early 1960s,
wolves could cross between Isle Royale and Canada by way of seasonal ice
bridges, which formed during three out of the first four winters of the
Michigan Tech study. But rising temperatures have made ice bridges increasingly
rare. In the past two decades, only three winters have been cold enough for ice
bridges to form. And only one of those seasonal links, in 1997, brought a new
wolf to the island: a grizzled male that Peterson and Vucetich call the Old
Grey Guy.

The Old Grey Guy may have saved the
Isle Royale wolves from extinction. By the time he arrived, the island
population had dropped to around 24 individuals and every wolf skeleton
the
researchers examined showed deformities in the spine. The population had
fallen to 14 wolves by the time the first of Old Grey Guy’s progeny
were born. But even a team of
leading geneticists couldn’t pinpoint the root of the problem.

“We didn’t know what the problem was at that
time,” Peterson said. But more wolf pups began to survive after the Old
Grey Guy came into the picture, and Peterson’s team was able to prove that the
population had been suffering from genetic depression. Simply
put, without newcomers like the Old Grey Guy arriving from the mainland, the
wolves of Isle Royale face a limited selection of mates, and they become
inbred.

The
Case for New Blood

The Old Grey Guy was the last wolf to
migrate to Isle Royale from the outside world. If wolves are to persist on Isle
Royale, Peterson and Vucetich say a genetic rescue will be necessary. In other
words, they want to bring fresh DNA to the breeding mix by importing wolves
from mainland populations. This radio-collared wolf fell through ice around the island in 2005 and washed ashore in the following spring. Photo: John Vucetich

• • •

They see two imperatives for this move:
First, because climate models point to a future of warmer winters in this
region, the wolves are unlikely to survive another generation without
intervention. Second, because wolves keep moose populations in check, the
disappearance of this predator would have cascading effects throughout the
island ecosystem, allowing growing moose herds to overgraze on plants that that
are already suffering negative impacts related to climate change.

Other scientists oppose the idea of
meddling with a population that offers such a unique opportunity to observe and
analyze trends in a natural laboratory over the long term. “The best thing we can do, for
scientific purposes, is to just watch the situation,” former
Isle Royale wolf ecologist Dave Mech told me in an interview for Al
Jazeera America last spring. He’s
concerned that monkeying with the wolf population would taint the scientific
record, which has thus far been based only on observing the species.After completing a necropsy, John Vucetich waits for Don Glaser to pick him up in the research plane.Photo: John Vucetich (self-portrait)
Further complicating matters is Isle
Royale’s designation as capital-W Wilderness — public land designated for the highest level of conservation protection under federal law. That designation makes it off-limits to intervene
with the natural ecosystem. Peterson and Vucetich argue, however, that climatic changes
are not, in fact, natural, but rather are proof of the ways humans are
trammeling (to use wording from the Wilderness Act)
on nature in indirect ways.

For now, the National Park Service is taking a wait-and-see
approach. In April, Isle Royale superintendent Phyllis
Green announced that the park service would be taking no actions in the near
term to perform genetic rescue and that it would instead conduct a three-year
environmental impact study to ascertain not only the impacts of climate change
on the island’s wolves, but also its entire ecosystem. The study was supposed
to begin this fall, but a lack of funding meant the study will not commence
until 2015 at the earliest.

When Science and
Advocacy Meet

When asked if he considers himself an advocate, Peterson
says “We’re advocates for science and education, for sure.” What
about for wolves? “Through science and education, yes. There are sometimes
abusive decisions made — abusive to the conservation of wildlife. And it’s important
to study those issues carefully and, where appropriate, make noise about
them.”Rolf
Peterson inspects a moose vertebrae for signs of arthritis, which would
have made it more susceptible to predation. Taken in February 2014.Photo: John Vucetich
Vucetich has written about the issue of advocacy in the
sciences for the journal Conservation Biology,
and endured criticism for it. “There are some people who tell us we should
not be doing anything that scientists aren’t expected to do,” says
Peterson. “Advocacy is one word, crossing the line is another phrase.
Passion. They say it’s OK to be passionate but you gotta know when to say
‘enough.’”

Vucetich, however, is undeterred. He said controversy like
this comes with the job. “I think there might be some self-selection early
on among wolf ecologists, figuring out what their tolerance is in getting
engaged [in social or policy issues].”

The film offers an abbreviated history of the relationship between wolves and people—told from the wolf’s perspective—from a time when they coexisted to an era in which people began to fear and exterminate the wolves.

The return of wolves to the northern Rocky Mountains has been called one of America’s greatest conservation stories. But wolves are facing new attacks by members of Congress who are gunning to remove Endangered Species Act protections before the species has recovered.

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Inescapably, the realization was being borne in upon my preconditioned mind that the centuries-old and universally accepted human concept of wolf character was a palpable lie... From this hour onward, I would go open-minded into the lupine world and learn to see and know the wolves, not for what they were supposed to be, but for what they actually were.

-Farley Mowat, Never Cry Wolf

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“If you look into the eyes of a wild wolf, there is something there more powerful than many humans can accept.” – Suzanne Stone